FIG. 1 shows an example of a planar microlens array in which an array of large number of tiny convex lenses and an array of large number of tiny concave lenses form a layered structure. The microlens array has a high refractive resin layer 2 and a low refractive resin layer 3, laminated one on the other, between transparent substrates 1 made of, e.g., glass plate.
Usually, a layer serving as a concave lens function is constituted by a low refractive resin, while a layer serving as a convex lens function is constituted by a high refractive resin.
Such microlens arrays are used in optoelectronic equipment such as CCD, liquid crystal projectors, camcorders, viewfinders, and portable TV sets.
Conventional high refractive resins known to be practically useful in the microlens arrays include ultraviolet-curing acrylic resins and epoxy resins, the refractive indices of which ranges about 1.57 to 1.68. Various microlens arrays using these resins have been proposed to date as disclosed, e.g., in JP 2000-2803 A (page 3), JP 2001-272507 A (page 5), and JP 2000-321675 A (pages 3-4).